Remove core animation assertion in reactive property.
Remove core animation assertion in reactive property.

Summary: We'll need to find a more effective solution for identifying when a property does or does not support receiving core animation events.

Reviewers: O2 Material Motion, O4 Material Apple platform reviewers, #material_motion, appsforartists

Reviewed By: O2 Material Motion, #material_motion, appsforartists

Subscribers: appsforartists

Tags: #material_motion

Differential Revision: http://codereview.cc/D2696

material-motion/material-motion-swift,material-motion/material-motion-swift